1 // SNES SPC-700 APU emulator
2
3 // snes_spc 0.9.0
4 #ifndef SNES_SPC_H
5 #define SNES_SPC_H
6
7 #include "SPC_DSP.h"
8 #include "blargg_endian.h"
9
10 struct SNES_SPC {
11 public:
12 typedef BOOST::uint8_t uint8_t;
13
14 // Must be called once before using
15 blargg_err_t init();
16
17 // Sample pairs generated per second
18 enum { sample_rate = 32000 };
19
20 // Emulator use
21
22 // Sets IPL ROM data. Library does not include ROM data. Most SPC music files
23 // don't need ROM, but a full emulator must provide this.
24 enum { rom_size = 0x40 };
25 void init_rom( uint8_t const rom [rom_size] );
26
27 // Sets destination for output samples
28 typedef short sample_t;
29 void set_output( sample_t* out, int out_size );
30
31 // Number of samples written to output since last set
32 int sample_count() const;
33
34 // Resets SPC to power-on state. This resets your output buffer, so you must
35 // call set_output() after this.
36 void reset();
37
38 // Emulates pressing reset switch on SNES. This resets your output buffer, so
39 // you must call set_output() after this.
40 void soft_reset();
41
42 // 1024000 SPC clocks per second, sample pair every 32 clocks
43 typedef int time_t;
44 enum { clock_rate = 1024000 };
45 enum { clocks_per_sample = 32 };
46
47 // Emulated port read/write at specified time
48 enum { port_count = 4 };
49 int read_port ( time_t, int port );
50 void write_port( time_t, int port, int data );
51
52 // Runs SPC to end_time and starts a new time frame at 0
53 void end_frame( time_t end_time );
54
55 // Sound control
56
57 // Mutes voices corresponding to non-zero bits in mask (issues repeated KOFF events).
58 // Reduces emulation accuracy.
59 enum { voice_count = 8 };
60 void mute_voices( int mask );
61
62 // If true, prevents channels and global volumes from being phase-negated.
63 // Only supported by fast DSP.
64 void disable_surround( bool disable = true );
65
66 // Sets tempo, where tempo_unit = normal, tempo_unit / 2 = half speed, etc.
67 enum { tempo_unit = 0x100 };
68 void set_tempo( int );
69
70 // SPC music files
71
72 // Loads SPC data into emulator
73 enum { spc_min_file_size = 0x10180 };
74 enum { spc_file_size = 0x10200 };
75 blargg_err_t load_spc( void const* in, long size );
76
77 // Clears echo region. Useful after loading an SPC as many have garbage in echo.
78 void clear_echo();
79
80 // Plays for count samples and write samples to out. Discards samples if out
81 // is NULL. Count must be a multiple of 2 since output is stereo.
82 blargg_err_t play( int count, sample_t* out );
83
84 // Skips count samples. Several times faster than play() when using fast DSP.
85 blargg_err_t skip( int count );
86
87 // State save/load (only available with accurate DSP)
88
89 #if !SPC_NO_COPY_STATE_FUNCS
90 // Saves/loads state
91 enum { state_size = 67 * 1024L }; // maximum space needed when saving
92 typedef SPC_DSP::copy_func_t copy_func_t;
93 void copy_state( unsigned char** io, copy_func_t );
94
95 // Writes minimal header to spc_out
96 static void init_header( void* spc_out );
97
98 // Saves emulator state as SPC file data. Writes spc_file_size bytes to spc_out.
99 // Does not set up SPC header; use init_header() for that.
100 void save_spc( void* spc_out );
101
102 // Returns true if new key-on events occurred since last check. Useful for
103 // trimming silence while saving an SPC.
104 bool check_kon();
105 #endif
106
107 public:
108 BLARGG_DISABLE_NOTHROW
109
110 typedef BOOST::uint16_t uint16_t;
111
112 // Time relative to m_spc_time. Speeds up code a bit by eliminating need to
113 // constantly add m_spc_time to time from CPU. CPU uses time that ends at
114 // 0 to eliminate reloading end time every instruction. It pays off.
115 typedef int rel_time_t;
116
117 struct Timer
118 {
119 rel_time_t next_time; // time of next event
120 int prescaler;
121 int period;
122 int divider;
123 int enabled;
124 int counter;
125 };
126 enum { reg_count = 0x10 };
127 enum { timer_count = 3 };
128 enum { extra_size = SPC_DSP::extra_size };
129
130 enum { signature_size = 35 };
131
132 private:
133 SPC_DSP dsp;
134
135 #if SPC_LESS_ACCURATE
136 static signed char const reg_times_ [256];
137 signed char reg_times [256];
138 #endif
139
140 struct state_t
141 {
142 Timer timers [timer_count];
143
144 uint8_t smp_regs [2] [reg_count];
145
146 struct
147 {
148 int pc;
149 int a;
150 int x;
151 int y;
152 int psw;
153 int sp;
154 } cpu_regs;
155
156 rel_time_t dsp_time;
157 time_t spc_time;
158 bool echo_accessed;
159
160 int tempo;
161 int skipped_kon;
162 int skipped_koff;
163 const char* cpu_error;
164
165 int extra_clocks;
166 sample_t* buf_begin;
167 sample_t const* buf_end;
168 sample_t* extra_pos;
169 sample_t extra_buf [extra_size];
170
171 int rom_enabled;
172 uint8_t rom [rom_size];
173 uint8_t hi_ram [rom_size];
174
175 unsigned char cycle_table [256];
176
177 struct
178 {
179 // padding to neutralize address overflow
180 union {
181 uint8_t padding1 [0x100];
182 uint16_t align; // makes compiler align data for 16-bit access
183 } padding1 [1];
184 uint8_t ram [0x10000 + 0x100];
185 } ram;
186 };
187 state_t m;
188
189 enum { rom_addr = 0xFFC0 };
190
191 enum { skipping_time = 127 };
192
193 // Value that padding should be filled with
194 enum { cpu_pad_fill = 0xFF };
195
196 enum {
197 r_test = 0x0, r_control = 0x1,
198 r_dspaddr = 0x2, r_dspdata = 0x3,
199 r_cpuio0 = 0x4, r_cpuio1 = 0x5,
200 r_cpuio2 = 0x6, r_cpuio3 = 0x7,
201 r_f8 = 0x8, r_f9 = 0x9,
202 r_t0target = 0xA, r_t1target = 0xB, r_t2target = 0xC,
203 r_t0out = 0xD, r_t1out = 0xE, r_t2out = 0xF
204 };
205
206 void timers_loaded();
207 void enable_rom( int enable );
208 void reset_buf();
209 void save_extra();
210 void load_regs( uint8_t const in [reg_count] );
211 void ram_loaded();
212 void regs_loaded();
213 void reset_time_regs();
214 void reset_common( int timer_counter_init );
215
216 Timer* run_timer_ ( Timer* t, rel_time_t );
217 Timer* run_timer ( Timer* t, rel_time_t );
218 int dsp_read ( rel_time_t );
219 void dsp_write ( int data, rel_time_t );
220 void cpu_write_smp_reg_( int data, rel_time_t, int addr );
221 void cpu_write_smp_reg ( int data, rel_time_t, int addr );
222 void cpu_write_high ( int data, int i, rel_time_t );
223 void cpu_write ( int data, int addr, rel_time_t );
224 int cpu_read_smp_reg ( int i, rel_time_t );
225 int cpu_read ( int addr, rel_time_t );
226 unsigned CPU_mem_bit ( uint8_t const* pc, rel_time_t );
227
228 bool check_echo_access ( int addr );
229 uint8_t* run_until_( time_t end_time );
230
231 struct spc_file_t
232 {
233 char signature [signature_size];
234 uint8_t has_id666;
235 uint8_t version;
236 uint8_t pcl, pch;
237 uint8_t a;
238 uint8_t x;
239 uint8_t y;
240 uint8_t psw;
241 uint8_t sp;
242 char text [212];
243 uint8_t ram [0x10000];
244 uint8_t dsp [128];
245 uint8_t unused [0x40];
246 uint8_t ipl_rom [0x40];
247 };
248
249 static char const signature [signature_size + 1];
250
251 void save_regs( uint8_t out [reg_count] );
252 };
253
254 #include <assert.h>
255
sample_count()256 inline int SNES_SPC::sample_count() const { return (m.extra_clocks >> 5) * 2; }
257
read_port(time_t t,int port)258 inline int SNES_SPC::read_port( time_t t, int port )
259 {
260 assert( (unsigned) port < port_count );
261 return run_until_( t ) [port];
262 }
263
write_port(time_t t,int port,int data)264 inline void SNES_SPC::write_port( time_t t, int port, int data )
265 {
266 assert( (unsigned) port < port_count );
267 run_until_( t ) [0x10 + port] = data;
268 }
269
mute_voices(int mask)270 inline void SNES_SPC::mute_voices( int mask ) { dsp.mute_voices( mask ); }
271
disable_surround(bool disable)272 inline void SNES_SPC::disable_surround( bool disable ) { dsp.disable_surround( disable ); }
273
274 #if !SPC_NO_COPY_STATE_FUNCS
check_kon()275 inline bool SNES_SPC::check_kon() { return dsp.check_kon(); }
276 #endif
277
278 #endif
279